Google looks to be playing some expensive defense against Facebook, as the two companies are vying to buy Israeli satellite mapping startup Waze, reports Reuters. Facebook is reportedly offering $1 billion for Waze, so if Google wants to try and block Facebook from getting into the mobile mapping game, it’s going to cost them.

According to the report, nothing is set in stone either way, although Facebook has apparently been in talks with Waze for six months.

Waze is a unique mapping service in that it relies on crowd-sourced data from its 47 million users to deliver real-time traffic information for turn-by-turn GPS navigation. Clearly, it would be a great asset, and Google might also want to acquire it to augment its own excellent Google Maps.

Securing an excellent mapping tool for your platform is a huge get; for one thing, people use maps a lot, and for another, it’s really hard to build your own service. For instance, we all saw what happened when Apple haughtily tried to ditch Google Maps on iOS (in case you missed it, it was a disaster).

Whoever wins Waze will be getting a hugely valuable property, but it will cost a lot of money. Fortunately for Facebook and Google, they both have large coffers.